Vacuum-pan.



BATENTED JULY 21, 1903.-

N. GERBER. VAGUUM PAN.

APPLIOATION FILED JAN. 27, 1902.

in. was.

UNITED STATES.

' PATENT rammed ma 21, 1. 905.

OFFICE.

VAC U uivl PAN.

SPECIFICATION forming part o Letters Patent N0. 734,228, date d July 21, 1903.

Application iiled ll'annary 27,19012- Serial No. 91 ,458. (Nomodel-l I To all whom it may c07 wern.- Be it known that I, NICHOLAS GERB R, a

citizen of Switzerland, residing at Zurich,'.

Switzerland, have invented newand useful Improvements in Continuous Evaporators, of which the following is a specification.

This invention has relation to evaporators; and it has forits object certain improvements,

hereinafter fully described, whereby the effi ciency of the apparatus is materially enhanced and thecost of operating the same re'- duced.

In the accompanying drawings, Figure lis an elevation, partly in section; and 2, a plan View of an evaporatorembodying my invention.

forcing fan 8, and the standard s'has formed thereon or secured thereto aconsole c for a I steam-engine 11, whose piston is eonnectedby. a connecting-rod r to a crank C on the driving-shaft 10, which has its bearings in the up:

per ends of thestandards s and's'and carries' I The belt-pulley P is belted to a pulley p on a stirrer-shaft 5,-'

two belt-pulleys P and P.

the belt being suitably guided by a pulley 39 the upper endof said shaft 5 having its bearing in a bracket 5 secured to the cross-beam b. The pulley P isbeltedlb'y belt9 we p111; ley p on the driving-shaft of the suction and,

forcing fan 8, and the speed ofthe engine is controlled by a governor 12' of any usual 'or preferred construction, the governor-spindle having its bearings in a ring-bracket b fon the cross-beam l) and being geared to the drivingshaft 10 through gears g g.

On the frame-base b is arranged a vessel 13, constructed of a material that is a non-condoctor of heat-as'Wood, for instance-in the bottom of which vessel is formed an-axial aperture in which is stepped fluid-tight the tubular axial foot of the sheet-metal evaporating-pan 1, .both vessels being of cylindrical form in cross-section.

The evaporating-pan 1 projects above the containing vessel 13 and is of less diameter than the latter and has an axial tubular openended feed-channel 1', extending from below (the bottom of the pan a considerable distance thereinto, and is provided at its outer end with a tubularfextension or foot of reduced jdiameter, whereby the bottom of the pan is suitably spaced from the bottom of vessel 13 to form an encompassing heating-chamber 13',

closed fluid-tight at its upper end by any suitable means. The evaporating-pan isclosed by aremovable cover 6, which is connected by pipe 7 with'theexha'ust-fan8, which latter is not'here used to produce a vacuum in vessel 1, though it may be soused,if necessary, but to exhaust the hot vapors-for the purpose of utilizing them in heating the liquid to ,be evaporated, witha view to economy of the heating medium. To diametrically oppositesides of a suitablebase b are secured standardsjs and 8, connected near their upper ends by a cross-beam- The standard 8 has formed thereon or $6- cured thereto a console cv for a suction'and Inthe tubular foot of theaxial feed-channel I provide a bearing inwhich is stepped the stirrer-shaft 5 which latter, with a view to facilitating access to the pan 1, I make in two parts coupled together in any desired well-known manner, as by a sleeve-coupling 0 To the aforesaid foot of pan 1 is connected the feed-pipe 21, (shown in dotted lines "in Fig. 1,)through which the liquid to be evaporated isfed, and 20 is a valved drain- "pipe for draining from' vessel 13 the hot wa ter, if such be used as a heating medium, or the water'of condensation, .if steam be used. I also provide a pipe 19 for the outflow from chamber 13.of the hot water or steam and a valved air-exhaust pipe 17,-having vertical branch pipes projecting into external channels in the bottom of the .pan, hereinafter referred. to,-for exhausting the air from the heating-chamber as the hot water or steam is or both are admitted thereto in'starting the evaporation. I -Hot water is supplied to the heating-chamberl3"near the. bottorn through a pipe 14, and the exhaust-steam from the engine 11 is exhausted into said chamber through a pipe 15, which has a branch pipe 16, adapted to be connected to a source of live-steam supply (not shown) for said engine, all-these pipes being provided with suitable valves or stopcocks (not shown,) while the condensate is exhausted from the evaporating-pan 1 near its upper end through a pipe 22.

With a view to expediting the evaporation by providing as large an evaporating-surface as possible without increasing or materially ICO increasing the dimensions of the evaporatingpan I provide the bottom of the pan with alternating internal and external circular channels of a depth equal to about two-thirds of the depth of the pan, the axial feed-channel 2 projecting a like distance into said pan, said channels having in cross-section the form of a hollow cone open at its base.

To the shaft 5 within the tubular axial channel 2 is secured a sleeve provided with stirrer-blades 3 of such a width that their edges will rotate in close proximity to the channel-wall, and said shaft carries a deflector 24, having circular channels whose outer edges are bent downwardly and overlap the upper edges 1 of the circular channelwalls, so as to leave a narrow passage between said edges and the inner faces of the circular channels in said disk 24:, the latter being also provided with radial slots for the passage of the stirrer-blades 3.

The disk 24: is preferably provided with a long hub for securing it to shaft 5, and above the disk 24 said hub has radial arms 4, to which are secured stirrer-blades 3 and 3 of a shape to fit the cross-sectional configuration of the circular channels, said blades extending almost to the bottom thereof, their edges rotatingin close proximity to the channel-walls. The outer stirrer-blades 3 are longer than the intermediate blades 3 and extend nearly to the outflow-pipe 22 for the condensate, their edges also rotating in close proximity to the inner periphery of the pan 1.

From the description of the construction of the vaporizing apparatus its general operation will be readily understood. I may, however, call special attention to the mode of feeding the liquid to be evaporated to the pan 1.

The feed of the liquid to the axial tubular channel 2 should be so regulated as to quantity to allow the liquid to be carried up along the walls of said channel by centrifugal action resulting from the rapid rotation of the stirrers 3, thereby causing a thin sheet or tilm of such liquid to be subjetfi d tdheat as it'flows upward along the heated channelwalls, and to flow over ina thin sheet or film into the adjacent circular channel controlled by the deflector-disk 24 to be subjected to the heat of the inner wall of said channel and then rise therein under centrifugal action, resultingfrom the rotation of the stirrerblades 3 along the outer heated wall thereof, and flow over the inner heated wall of the outer circular channel and rise under centrifugal action resulting from the rotation of the blades 3 along the inner wall of pan 1 to the outflow-pipe 22, the liquid being kept in continuous circular motion. During the evaporation the hot vapors are exhausted from the pan 1 and may be or preferably are utilized for heating the liquid to be vaporized, so that the latter passes 01' may pass from its reservoir to the pan at about the temperature of the exhaust-vapors for purposes hereinabove stated. According to the character of the liquid to be condensed I may use hot water or hot water and the exhauststeam from the engine, or I may use moderately-heated water and live steam, or I may use exhaust-steam only or live steam only.

In the evaporation or condensation of liquids, a i n il k,, which are liable to burn when brought into contact with highly-heated surfaces I employ the water-bath as a source of heat-supply, in conjunction with the exhaust-steam from the engine, as a means for utilizing the heat thereof, which would or might otherwise be wasted. On the other hand, for such liquids as can be condensed without injury by other heating media I can use live steam together with exhaust-steam. Finally it will readily be understood that the described apparatus may be used as a cooler or refrigerator. by substituting a refrigerant for the heating medium. This is of importance, especially in the production of highly-condensed milk, whose quality is very materially enhanced if the condensate is cooled immediately after condensation or at least before it cools down to atmospheric temperature under atmospheric influences, while the operations of condensation and cooling can be carried on simultaneously by providing two apparatuses such as described.

Having thus described my invention, what Iclaim as new therein, and desire to secure by Letters Patent, is-

1. An evaporating-pan comprising closed concentric vessels forming between them a heating-chamber, the inner vessel having in its bottom concentric alternating external and internal channels of a depth exceeding one-half the depth of said vessel, means for supplying heat to and exhausting the heating medium from the heating-chamber, and means for exhausting vapor from the inner vessel, for the purpose set forth.

2. A cylindrical evaporating-pan having deep'concentric alternating internal and external channels in its bottom, said channels of conical form in cross-section, and an axial tubularfeed-channelextendingfrom said bottom to the upper or inner edge of the channel-walls, for the purpose set forth.

3. A cylindrical evaporating-pan having deep concentric alternating internal and external channels in its bottom, and an axial tubular feed-channel extending from below said bottom to the upper orinner edge of the concentric channel-walls, said feed-channel having a tubular extension of reduced diameter at its outer end, in combination with an encompassing vessel forming a chamber around the pan, the outer vessel having in its bottom an aperture for the reception of the tubular extension of the feed-channel of the pan, for the purpose set forth.

4. A cylindrical evaporating vessel having deep, concentric alternating internal and external channels, and an axial circular feedchannel extending from below the bottom of the pan to the upper edge of the channelwalls and having a tubular extension of re duced diameter at its outer end, and an encompassin g vessel forming a chamber between it and the pans, the outer vessel provided with an aperture in its bottom for the reception of the aforesaid extension of the axial feed-channel; in combination with a revoluble shaft carrying stirrer-blades extending nearly to the bottom of the aforesaid internal concentric and axial channels and of a slightly smaller diameter than said channels, for the purpose set forth.

5. A cylindrical evaporating vessel'having deep, concentric alternatinginternal and external channels, and an axial circular feedchannel extending from below the bottom of the pan to the upper edge of the channelwalls and having a tubular extension of reduced diameter at its outer end, and an encompassingvessel forming a chamber between it and the pans,'the outer vessel provided with an aperture in its bottom for the reception of the aforesaid extension of the axial feed-channel; in combination with a revoluble shaft carrying stirrer-blades extending nearly to the bottom of the aforesaid internal concentric and axial channels and of a slightly smaller diameter than said channels, and a circularly-channeled deflecting-disk on said shaft proximate to the upper edges of the internal channel-walls, said disk having the outer walls ofits channels bent downward and overlapping the aforesaid upper edges of the channel-walls, for the purpose set forth.

6. A cylindrical evaporating-pan having alternating internal and external deep circular channels in itsvbottom and an axial tubular feed-channel extending from below said bottom to the upper edge of the circular channel-walls and provided at its outer end with an extension of reduced diameter, an encompassing vessel forming a chamber between it and the pan from which the latter projects, a fluid-tight joint between the pan and the upper end of the outer vessel, the latter having an aperture in its bottom in which the extension of the aforesaid feed-channel is fitted fluid-tight, a feed-pipe fitted to said extension, means for supplying a heating or cooling agent to the aforesaid chamber, means for exhausting such agent near the upper end thereof, and a valved air-exhaust pipe having branches extending upwardly into the external circular channels in the bottom of the pan; in combination with a revoluble stirrershaft carrying stirrer-blades extending into the internal circular channels of said bottom, for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

NICHOLAS GERBER. Witnesses:

A. LIEBERKNECHT, A. MATTI. 

